If that is the case, they are in fact showing you very annoying ghosts in their scenes. Hope they didn’t mean these statements. FXAA is not looking good to my taste, and combining it with TAA that is doubles the bad ideas for me. No thanks, sir 
They should have went with the T+SMAA, that was almost as good as the TAA but responsive. Except the ghosts, that i hated in that too.
This statement is also invalid, however your findings are appears to be interesting indeed. TAA is producing great many artifacts, ghosting can and will happen without motion blur enabled as well. All you have to do is just connect a noise node to that floor and you will see the problem. While a noise node maybe a strong case, it’s an easy example to reproduce one of the many artifacts. SSR is also being distorted while you move (especially on faster speeds), and pixels in cases can appear with invalid brightness, so these issues are always the fault of the TAA itself.